Method for casting a material, utilization of the method, casting mould for implementing the method and objects manufactured in accordance with the method and in the casting mould, as well as core for being inserted into such a casting mould

ABSTRACT

The invention pertains to methods for manufacturing objects in moulds, the moulds used for the manufacture and objects manufactured in accordance with the method and/or in the moulds.

The invention pertains to a method for casting a material that is initially transferred from its solid state into a free-flowing state and subsequently poured into a mould, in which the material solidifies. The invention furthermore pertains to moulds for implementing the method and objects that are or were manufactured in accordance with the method and/or in such moulds. The invention ultimately also pertains to a core that this inserted into such moulds.

Among gravity casting methods, four casting methods essentially have prevailed, namely bottom casting, lateral casting, top casting and tilt casting. A detailed description of these casting methods can be found in DE 10 2006 058 145 A1.

It is known that so-called mould cores or cores or core assemblies are required in the manufacture of castings with hollow spaces or with particularly complex geometries.

It is also known that such mould cores frequently cause defects in the casting and, in particular, impair the cast surface of the casting. Time-consuming operations are required in order to repair such defects in the cast surface. This type of subsequent or finish processing is complicated and therefore costly, in particular, on complex castings that need to fulfill very strict quality requirements.

Based on this state of the art, the invention aims to avoid the disadvantages of the cited casting methods and to develop methods for casting materials that make it possible to reduce or even entirely dispense with the costly subsequent or finish processing of castings, particularly in the casting of complex castings. The invention furthermore aims to make available such a method that ensures a high and constant quality of the castings being manufactured. The cycle, material, energy and transport efficiency should also be improved. Another objective of the invention consists of making available a generic method that is particularly harmless to the environment.

According to the invention, the method for casting a material by transferring said material into a free-flowing state by means of heating and introducing the material into a casting mould is characterized in that the introduction of the material into the casting mould is at least partly realized with the aid of tilt casting or the tilt casting principle and a core moulded of core moulding material and an inorganic binder is inserted into the casting mould in advance.

Although a person skilled in the art had to fear that an inorganic core is destroyed or fractures during tilt casting, it was surprisingly determined that the inventive method makes it possible to manufacture highly integrated and complex castings that are characterized by an improved surface. Consequently, the surface advantageously contains no or only isolated defects caused by the inserted core such as pores, shrink holes or veins. In this context, the inventive casting process in the form of a combination of tilt casting and an inorganic core that is inserted in advance proved particularly advantageous. The method makes it possible to manufacture complex castings of high quality, wherein a reduction of the costly subsequent or finish processing or treatment is simultaneously achieved. The latter usually form the main bottlenecks in production of castings. It is therefore possible to reduce the cleaning and control costs.

Another advantageous aspect is the environmental compatibility of the inventive method. Emissions and odors during the manufacture of castings are avoided or reduced because only small amounts of organic compounds or decomposition products, if any, are released during the casting process due to the utilization of an inorganic core.

Sand or silica sand is preferably used as core moulding material. This material in the form of a process residue of sorts is particularly well suited for recycling after the casting process.

It also proved particularly advantageous that no core dressing needs to be applied onto the core in order to produce a largely flawless and smooth surface of the casting. This eliminates another costly production step. It was determined that the combination of tilt casting and an inorganic core without dressing results in a particularly flawless surface, i.e., a surface without or with only a few shrink holes, pores or veining defects. It is therefore possible to cast complex castings of high quality, the subsequent or finish processing of which would be very difficult in accordance with the state of the art, wherein this subsequent or finish processing is now largely expendable in accordance with the invention. The disadvantageous adhesion of dressing on the castings being manufactured is advantageously eliminated. Despite the lack of dressing, it was impossible to detect any core mould material or sand adhering to the casting in the inventive combination of tilt casting and an inorganic core without dressing. The cleaning and control costs can be reduced in this fashion.

The inorganic binder used preferably consists of a binder on the basis of silicate, borate and/or phosphate. This results in an additionally improved reduction of possible casting defects. According to the invention, pores and shrink holes occur much less frequently.

The invention also pertains to the utilization of the inventive method for manufacturing complex castings, preferably pump housings, particularly high-pressure pump housings, or turbocharger housings.

The invention also pertains to a tiltable mould or a tiltable permanent mould, particularly for implementing the inventive method, wherein a core moulded of core moulding material, preferably of sand, and an inorganic binder is inserted into the mould. This significantly reduces the effort for cleaning the mould, particularly at the core locating points. The tools are preserved and have a longer service life.

The invention furthermore pertains to castings that are or were manufactured in accordance with the inventive method and/or by means of the inventive casting moulds, wherein these casting products consist of light metal alloys such as, in particular, aluminum alloys that are advantageously manufactured in accordance with the gravity method.

The invention ultimately also pertains to a core for being inserted into a casting mould that can be at least partly tilted in accordance with the tilt casting principle, wherein the core is moulded of a core moulding material, preferably of sand, with an inorganic binder, preferably on the basis of silicate, borate and/or phosphate. 

1. A method for casting a material by transferring said material into a free-flowing state by means of heating and introducing the material into a casting mold, wherein the introduction of the material into the casting mold is at least partly realized with the aid of the tilt casting principle, wherein a core molded of core molding material and an inorganic binder is inserted into the casting mold in advance.
 2. A method, particularly according to claim 1, wherein sand is used as core molding material.
 3. A method, particularly according to claim 1, wherein no core dressing is applied onto the core.
 4. A method, particularly according to claim 1, wherein an inorganic binder on the basis of silicate, borate and/or phosphate is used.
 5. The utilization of the method according to claim 1 for manufacturing a pump housing, particularly a high-pressure pump housing, or a turbocharger housing.
 6. A tiltable casting mold or tiltable permanent mold, particularly for implementing the method according to claim 1, wherein a core molded of core molding material, preferably sand, and an inorganic binder is inserted into the mold.
 7. A casting product, wherein it is manufactured in accordance with claim 1 or in a tiltable casting mold wherein a core molded of core molding material, preferably sand, and an inorganic binder is inserted into the mold.
 8. A casting product, wherein it consists of a light metal alloy such as, in particular, aluminum alloys that is advantageously manufactured by means of the gravity method in accordance with claim
 1. 9. A core for being inserted into a casting mold that can be at least partly tilted in accordance with the tilt casting principle, wherein the core is molded of a core molding material, preferably sand, with an inorganic binder, preferably on the basis of silicate, borate and/or phosphate. 